Thermal Delta-L Coupon

Thermal Delta-L Coupon

The Thermal Delta-L coupon is a dedicated test structure used to evaluate the electrical property stability of PCB materials under temperature variation.

By measuring changes in the electrical length of transmission lines across different temperature conditions, this method effectively captures the actual temperature-dependent behavior of the material dielectric constant (Dk).

How This Method Supports Engineers

This measurement approach enables engineers to:

• Validate material performance under real manufacturing processes and thermal environments

• Compare the thermal stability of different materials or process conditions

• Identify potential signal shift risks in high-frequency and high-speed applications at an early stage

Thermal Delta-L coupons are commonly applied in high-speed interface design, advanced material selection, and reliability qualification workflows, serving as a critical reference for design and material decision-making.